Switch structure



Sept. 11, 1934. E. H N 1,973,254.-

' SWITCH STRUCTURE Filed March 25. 1932 CURRENT SUPPLY Patented Sept. 11,1934

ama L PATENT OFFICE" SWITCH STRUCTURE Malcolm E. Henning, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des

a corporation of Iowa Moines, Iowa,

ApplicationMarch 25,- 1932, Serial No. 601,124 r 1 Claim. gci. 62-4) 3 One object of my invention is to, provide an automatic control switch structure including a pair of switches responsive to different conditions and constructed in a simple, durable and inex- 6 pensive manner.

A further object is to provide in a switch structure, a safety device for moving one of a pair of switches to off position, the safety device being operable independent of the normal automatic means which actuates the other switch.

Still a further object is to provide a switch structure for'controlling an electric circuit, including a pair of switches series connected with each other, automaticmeans being provided for controlling 160m of said switches according to normal conditions and the other switch being in the form of a safety switch to' operate upon occurrence of abnormal conditions only, it normally being un-' afiected and remaining in closed position.

A- further object is to provide an automatic switch structure having a pair of switches, each of which is constrained to closed circuit position by magnetic means, with a pair of actuating mechanisms responsive to different conditions, one condition normal and the other abnormal for operating the switches independent of each other. More particularly it is my object to provide a switch structure to be used for instance in a refrigerating system where means controlled by the temperature of the refrigerant automatically actuates one of the switches, while the pressure of the refrigerant itself may actuate the other switch,thereby"providing a safety means for discontinuing the electric circuit upon abnormal conditions occurring. Thus though temperature conditions call for continued operation of a refrigerant motor and compressor, an abnormal condition, such as clogging of the refrigerant pipes, may operate the other switch to prevent such operation of the motor.

This causes a shut-down of the refrigerating system until the pipes are cleaned out and thus again put in condition for proper operation of the refrigerating system.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attaine'd, as hereinafter more fully set forth, pointed out in my claim, and illustrated in the accompanying drawing, in which: I

Figure 1 is a side elevation of a switch structure embody ng my invention and showing it diagrammatically connected with a' refrigerating '5 system. r

between thearms 14 and 16 so that the arms Figure 2 is a reverse enlarged side elevation of the switch'structure, showing part of the struc ture broken away and other parts in section.

Figure 3 is a sectional view on'the line 3-6 of Figure 2; and

Figure 4 is a sectional view on the line 4-4 of Figure 3.

0n the accompanying drawing, I have used the reference numeral 10 to indicate a switch casing. Pivoted on a pin 12 therein is a main switch arm 14 and a safety switch arm 16. The switch arms 14 and 16 carry contacts 14a and 16a respectively for engagement with stationary contacts 14b and 16b. The contacts 14a and 16a are loosely mounted relative to the arms 14 and 16 and are carried by leaf springs 18.

Magnets 20 and 22 exert pull on the switch arms 14 and 16 to normally constrain them toward closed circuit positions.

The contact 14b is electrically connected with a terminal 140, while the contact 16b is-electrically connected with a terminal 160.

The pin 12 servesas an electrical connection are connected in series with the terminals 140 8.0 and 160 arid thus in series with any electrical circuit connected with the terminals.

The main switch arm 14 is operated by a temperature responsive bellows 24 opposed in its action by a spring 26. *A knob 28 is provided for adjusting the tension of thespring 26, but forms no part of my present invention. The bellows 24 and the spring 26 operatively engage a lever 30 pivoted at 32 and having itsopposite end hooked over a ball 34 which pivotally extends through an opening 35 in the arm 14.

From the construction of the parts just described, it will be obvious that a pressure or temperature decrease applied to the bellows 24 will permit the spring 26 to swing the lever 30 downwardly and thus exert a pull on the switch arm 14 to separate the contact 14a. from the contact 141; when such pull is suflicient to overcome the magnetic pull of the magnet 20 on the arm 14.

In Figure -1, I have shown a refrigerator .36 with a piping connection 38 between the bellows 24 and the interior of the refrigerator, so that the temperature in the refrigerator will automatically affect the bellows 24 and operate the switch arm 14. 1 10 The safety switch arm 16 is operated by a bellows 40 in the following described manner. An arm 42, preferably of insulation, is pivoted at 44 and has a slot 46. The slot 46 receives a .flnger 48 of a lever 50 also pivoted on the pin 110 safety switch arm 16, as best shown in Figure 4. It will thus be obvious that upward pressure on 5 the right hand end of the lever 42 suflicient to 1 overcome the pull of the magnet 22 on the arm '16 will separate the contact 16a from the contact 16b. The spring 52 will first be tensioned so that when separation does occur, it will occur with a snap action.

The bellows 40 is supported within a casing 54, which may be secured in any suitable manner to the switch casing 16. A lever 56 has pintles 58 extending through the casing 54: to provide a pivotal connection for the lever to the casing. The opposite end of the lever '56 engages the lever 42; A slot 59 in the casing 54 is provided as a stop for the lever 56, the lever having a finger 60' extending through the slot.

It will be obvious that pressure within the bellows 40 will raise the lever 56 and such raising is opposed by a spring 62. The tension of Referring to Figure 1, normal operation of the refrigerating system will cause lowering of the temperature in the refrigerator '36 until the bellows 24 has collapsed sufliciently to allow the spring 26 to separate the contact 140. from the contact 14b. Thus-the electric circuit to the mo:-,

, tor 74 is broken so that operation of the compressor 72 is stopped and thereupon the refrigerator 36 will gradually warm up until such time as the bellows 24 has expanded sufllciently to permit the magnet 20 to pull the switch arm 14 to closed circuit position. Thus normal automatic starting and stopping'of the refrigerating mechanism is efiected.

l Abnormal conditions occur sometimes, such as.

clogging of the pipes 70 or any of the other pipes of the refrigerating system and in such event,

the main switch 14 may be closed because of the remake temperature condition of the refrigerator 36 being high, but it is nevertheless desirable to stop the refrigerating system to prevent damage thereto. until the pipes have been cleaned out, or the dimculty otherwise remedied. Upon such clogging occurring,-excessive pressure will be built up in the pipe 68 and consequently in the bellows 46. This will raise the lever 56 and the lever 42 for causing the spring 52 to first exert tension on the safety switch arm 16 and then separate the contact 16m from the contact 16b against the action of the magnet 22. Thus the electric circuit will be broken upon abnormal pressure conditions and the switch 16 accordingly acts as a safety switch.

The bellows 40 is opposed by the spring 62 so that normally the stop finger 60 engages the bottom of the slot 59, but when excessive pressure is built up, the pressure overcomes the tension of the spring 62 to operate the safety switch.

The pressure at which the safety device will operate may be predetermined by adjusting the screw 64, so that if the safety device is to operate only at a very high pressure, the tension of the spring 62 can be increased, while if the safety operation pressure is to be low, the tension of the spring 62 may be decreased.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms'of structure 'or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

Refrigerating mechanism comprising a compressor, electric power means therefor, a cooling chamber, an evaporator therein, a high pressure conduit and a low pressure conduit connecting said compressor with said evaporator and a switch structure, said switch structure comprising a pair of switches series connected with each other and with said power means, magnetic means tending to close each of said switches, means actuated'by the temperature condition within said cooling chamber for opening one of said switches and means actuated by the pressure condition in said high pressure conduit for opening the other of said switches.

MALCOLM E. HENNING. 

